Overview
This mod adds 4 new coins (6 if you have brass or zinc from another mod) and 4 gems that can be used as a more simple application of currency in a server.
The aim of this mod is to have a fully physical currency for roleplay servers.
The process of making coins is so long for two reasons. It's more realistic than just slapping ingots in a crafting grid and it will discourage players from making counterfeit coins.
Casting Process
In order to make coins you'll have to cast a mold made out of the desired coin's base metal. First make a cast mold out of clay and smelt it to make a Coin Cast.
After that you'll want to smelt down some ingots (Blast Furnace is twice as fast for this). After you have your molten ingot of choice throw it in a crafting grid to get molten chunks. Combine a molten chunk with a coin cast to mold the metal into the shape of the coin. Now you'll have to cool down the metal by crafting it with a water bucket. Finally take the Coin Hammer (crafted with 6 iron ingots and a stick beneath them) and craft it with your cooled coin cast to make a coin!
Gem Cutting
Gem cutting is a lot more simplified. You simply need a Gem Cutter (crafted with four planks in the corners, any stone in the center, and iron ingots in the rest of the slots) and the gem of your choice. Throw them both in a crafting grid and you'll get 4 gems!
Coin Minting and Checking
The coins can be "minted" by holding a Coin Press (crafted with a piston with iron ingots in the adjacent slots) in your main hand and a coin in your offhand and right clicking.
Minting a coin adds your username and the month/year as NBT data to the coin.
Multiple coins can be minted at one time.
Gems can't be minted yet but will be able to in the future.
Coins can be checked with the Coin Checker (crafted with a glass pane in the center, iron ingots adjacent to it, and a stick in the bottom left corner) which allows you to see who minted it and when.
Hold the Coin Checker in your main hand and the coins/coin you wish to check in your offhand and right click.
Credits
Thank you David for your creative ideas and suggestions.
I made this mod for a roleplay server of mine and I may or may not continue to add features/ change things. If you have any suggestions please leave them in the comments.